Exp 7 IO & BSR Mode.pptx

Exp 7 IO & BSR Mode using 8085

1. Experiment No. 7 I/O & BSR Mode of 8255

2. Block diagram of 8255

3. Control word register (CWR) of 8255

4. Sample Problems on I/O Mode of 8255 PROBLEM 1) Assume I/O addresses of PA, PB, PC & CWR are 80H-83H respectively. Write an ALP to configure port A and port CL as output ports and port B and port CU as input ports in mode 0. Read switch positions connected to port A and turn on the respective LEDs of port B.

5. Main problem statement of the experiment on 8255 in simple i/o mode Statement: Assume I/O addresses of PA, PB, PC & CWR are 80H-83H respectively. Write an ALP to configure port A as Input port and port B as Output port in mode 0. Read 8-bit Port A status and send on to Port B continuously.

6. Flow Chart Start Get CWR I/O Mode format into Acc Read Port A status Send on to Port B Send to CWR Flow Chart of I/O mode of 8255 using 8085 microprocessor

7. Address Label Instruction Opcode 6700, 1 MVI A, 90H 3E, 90 2, 3 OUT CWR D3, 83 4, 5 IN PA DB, 80 6, 7 OUT PB D3, 81 8, 9, A JMP UP C3, 04, 67 B RST1 CF UP: I/O Mode program of 8255 using 8085 microprocessor

8. Control word register (CWR) of BSR Mode in 8255

9. Main problem statement of the experiment on 8255 in simple i/o mode Statement: Assume I/O addresses of PA, PB, PC & CWR are 80H-83H respectively. Write an ALP to SET PC2 & PC5 bit of Port C.

10. Flow Chart Start Get I/O Mode format to make all ports as output into Acc. Get BSR Mode format to SET PC2 into Acc. Send to CWR Send to CWR Get BSR Mode format to SET PC5 into Acc. Send to CWR Stop Flow Chart of I/O mode of 8255 using 8085 microprocessor

11. Address Label Instruction Opcode 6700, 1 MVI A, 80H 3E, 80 2, 3 OUT CWR D3, 83 4, 5 MVI A, 05H 3E, 05 6, 7 OUT PB D3, 83 8, 9 MVI A, 0BH 3E, 0B A, B OUT PB D3, 83 C RST1 CF BSR Mode program of 8255 using 8085 microprocessor